* Gums: The gums are pink tissue surrounding the teeth and bones; they constitute a barrier to the neck of the tooth. Inflammation of the gums is called gingivitis and inflammation reaches the bone there is presence of periodontitis.
* Alveolar bone: The bone of the jaw surrounding the teeth called alveolar bone. In the presence of periodontitis, the bone can be absorbed more slowly or less as a result of the presence of an inflammatory process.
* Periodontal ligament: The fibers of connective tissue located between the alveolar bone and tooth root, the periodontal ligament that holds teeth in place. What are the different kinds of teeth?
Each tooth has a task or function (Use the dental arch given in this section to locate and identify each type of tooth): 
* Incisive these anterior teeth, cutting chisel-shaped (four upper incisors, and four lower incisors) are used to cut food.
* Canines: these teeth used to tear food.
* Premolars these teeth have two cuspides edge on the surface of the teeth in front of the other jaw. The premolars are used for grinding and tearing.
* Molars: use these teeth to chew food, they have several cuspides on the surface of the teeth in front of the other jaw.